Duplex brake cylinder



E. E. HEWITT Jan. 25, 1938.

. ljUPLEX BRAKECYLINDER Filed Feb. 27, 1957 2 Sheets-Sheet 1 I mvmrox ELLISE.HEWITT KN 8N ATTORNEY.

Jan. 25', 1938.

E5. HEWITT DUPLEX BRAKE CYLINDER Filed Feb. 27, 1957 2 Sheets-Sheet '2 51.1.15 E. HEW ITT ATTORNEY.

Patented Jan. 25, 1938 UNITED STATES DUPLEX BRAKE CYLINDER Ellis E. Hewitt, Edgewood, Pa., assignor Westinghouse Air Brake Company,

to The Wilmerding, Pa., a corporation of Pennsylvania Application February 27, 1937, Serial No. 128,086

7 Claims. (circa-2) sure chamber of minimum volume between the pressure sides of the pistons.

Other objects and advantages will appear in the following more detailed description of the invention.

In the accompanying drawings, Fig. 1 is a longitudinal sectional view of a duplex cylinder mechanism embodying the invention, and Fig. 2 v

is an enlarged cross-sectional view of the mechanism taken on the line 2-2 of Fig. 1.

As shown, the duplex cylinder mechanism comprises axially aligned oppositely movable cup-shaped pistons I and 2 which are slidably mounted in longitudinally aligned cylinder casings 3 and 4, respectively. The adjacent ends of these cylinder casings are integrally connected together by an annular pressure head construction 5 which, as shown in Fig. 1 is V- shaped in cross-sectionpthe walls ii and l of the construction extending inwardly between the pressure faces of the pistons and converging toward each other and constituting stops for the pistons. These walls merge into each other some distance from the longitudinal axis of the cylinders so as to provide an opening 8 of fairly large diameter which constantly connects the pressure chambers 9 and iii of the cylinders 3 and 4 respectively.

Extending between and integral with the walls 8 and 1 are spaced radially arranged longitudinally extending strengthening ribs ll. Also extending between and integral with these walls is a header l2 which extends outwardly into the plane of the outer surface of the cylinder casing, the outer end of the header being provided with end walls l3 and I4. Each end wall is provided with a threaded opening which is in communication with a fluidpressure supply and release passage l5 leading 'to theopening 8.

.As shown in Fig. 2, the opening in either one of the header walls is adapted to i be eitherclosed by a, plug l6 which may be screwed into the wall or to accommodate a. supply or release pipe I? adapted to have screw-threaded connection with the casing. It will here be understood that the plug and pipe I! are interchangeable so as to accommodate different piping arrangements.

Each header end wall is also provided with "5 screw-threaded openings ill for the reception of bolts when it is desired to secure the supply and release pipe ,I! to the header by means of the well known reinforcing pipe flanges, not-shown.

The pistons may each be of the same con- 10 struction as those shown in Patent No. 2,055,104,

issued September 22, 1936 to William C. Landis and myself. Briefly described, each piston may comprise a cup-shaped piston head l9 having mounted thereon correspondingly shaped packings of the snap-on type having an annular thickened portion 2| which is located near the ,outer edge portion of the packing. Each piston is'provided with a hollowpiston rod 22 in which there is pivotally mounted, in the usual 20 manner, a push rod 23 which extends'through a centraiopening in the non-pressure head 24 secured to the cylinder casing. Interposed between and engaging the piston and non-pressure head is the'usual release spring 25.

Each non-pressure head 24 is provided with the usual breather opening 26 in which there is interposed the usual air strainer 27. "When the pistons i and 2 are moved to their normal release position as shown in Fig. 1 the thickened portions 2! of the piston packings engage the pressurehead of the cylinders and the pistons are brought to a stop by such engagement. Heretofore in duplex cylinder mechanisms the piston rods have been provided with stops which engage with the non-pressure heads of the cylinders to arrest the movement of the pistons in their normal release positions. By utilizing the pressure head construction 5 as a stop for the pistons the non-pressure heads are 40 relieved of this 'ofiice and as a result such heads may be made lighter than would otherwise be the case.

While one illustrative embodiment of the invention has been described in detail, it is not my intention to limit its scope to that embodiment or otherwise than by' the terms of the ap- .Dended claims.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A unitary cylinder casing comprising two longitudinally spaced axially aligned cylinder portions and an annular head'V-shaped in cross- .IB

PAT NT OFFICE portions, an annular head V-shaped in crosssection and integrally connecting said cylinder portions; and radially arranged longitudinally extending strengthening ribs integral with said cylinder portions.

4. A unitary cylinder casing comprising two longitudinally spaced axially aligned cylinder portions having two integral annular wall portions which extend inwardly toward the longitudinal axis of the cylinder portions and which converge toward each other and merge together about, but spaced away from, the longitudinal axis of the cylinder portions.

5. A unitary cylinder casing comprising two longitudinally spaced axially aligned cylinder portions having two integral annular wall portions which extend inwardly toward the longitudinal axis of the cylinder portions and which converge toward each other and merge together about, but spaced away from, the longitudinal axis of the cylinder portions, and radially arranged strength ening means extending between and integrally connected with said annular wall portions.

6. A unitary cylinder casing comprising two longitudinally spaced axially aligned cylinder portions having two integral annular wall portions which extend inwardly toward the longitudinal axis'of the cylinder portions and which converge toward each other and merge together about, but spaced away from, the longitudinal axis of the cylinder portions, the merging portions of said walls defining a communication always open to both cylinder portions, a header disposed between said walls having a passage through which fluid under pressureis adapted to be supplied to and released from said communication and thereby said cylinders.

7. A unitary cylinder casing comprising two longitudinally spaced axially aligned cylinder portions having two integral annular walls which extend inwardly toward the longitudinal axis of the cylinder portions and which converge toward each other and merge together about, but spaced away from, the longitudinal axis of the cylinder portions, a header integrally connected to said walls and having a passage through which fluid under pressure is adapted to be supplied to and released from said communication.

ELLIS E. HEWITT. 

